package ch18_IO;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;

/**
 * @author yuchao
 * Converting text to and from ByteBuffers
 */
public class BufferToText {
	private static final int BSIZE = 1024;
	public static void main(String[] args) throws IOException {
		FileChannel fc = new FileOutputStream("data2.txt").getChannel();
		fc.write(ByteBuffer.wrap("Some text".getBytes()));
		fc.close();
		fc = new FileInputStream("data2.txt").getChannel();
		ByteBuffer buff = ByteBuffer.allocate(BSIZE);
		fc.read(buff);
		buff.flip();
		//Doesn't work
		System.out.println(buff.asCharBuffer());
		//Decode using this system's default Charset:
		buff.rewind(); // back to start of the data
		String encoding = System.getProperty("file.encoding");
		System.out.println("Decoded using " + encoding + ": " + Charset.forName(encoding).decode(buff));
		// Or, we could encode with something that will print
		fc = new FileOutputStream("data2.txt").getChannel();
		fc.write(ByteBuffer.wrap("Some text".getBytes("UTF-16BE")));
		fc.close();
		// Now try reading again:
		fc = new FileInputStream("data2.txt").getChannel();
		buff.clear();
		fc.read(buff);
		buff.flip();
		System.out.println(buff.asCharBuffer());
		// Use a CharBuffer to write through:
		fc = new FileOutputStream("data2.txt").getChannel();
		buff = ByteBuffer.allocate(24);
		buff.asCharBuffer().put("Some text");
		fc.write(buff);
		fc.close();
		// Read and Display
		fc = new FileInputStream("data2.txt").getChannel();
		buff.clear();
		fc.read(buff);
		buff.flip();
		System.out.println(buff.asCharBuffer());
	}
}
